physics & astronomy

Yuanyuan Zhang

Date: 
Thursday, February 27, 2020 - 4:00pm to 5:00pm
Location: 
BL 339
Type of Event (for grouping events):

Jeong-Gyu Kim

Date: 
Thursday, April 30, 2020 - 4:00pm to 5:00pm
Location: 
BL 339
Type of Event (for grouping events):

Long-term Monitoring of Active Galactic Nuclei with the NASA Swift mission.

I will report on long-term monitoring campaign with the NASA Swift mission.
Besides the the NASA Flagship missions Chandra and HST, Swift is NASA's Number 1 mission.
While Swift was launched more than 15 years ago as a Gamma Ray Burst observatory
over the last decade it has morphed into the major tool for time-domain Astrophysics
including studies of Active Galactic Nuclei (AGN). These super-massive accreting black holes
in the center of galaxies are the most luminous persistent object in Universe. However, many
of these AGN display dramatic flux variations on the UV and X-rays which can be explain for
example by absorption and dramatic changes in the accretion rate.
In my talk I will first introduce the NASA Swift observatory and its achivement for Astrophysics
before I will discuss the results of AGN studies with Swift.
Date: 
Thursday, January 30, 2020 - 4:00pm to 5:00pm
Location: 
TBD
Tags/Keywords:
Type of Event (for grouping events):

Jeffrey Newman

Date: 
Thursday, February 6, 2020 - 4:00pm to 5:00pm
Location: 
BL 339
Tags/Keywords:
Type of Event (for grouping events):

A New Mask for An Old Suspect -- Testing the Sensitivity of the Galactic Center Excess to the Point Source Mask

The Galactic center excess has lingered as a possible, but ambiguous, signal of new physics for several years. It has previously been argued that certain details of the excess emission imply that it likely originates from a population of point sources, but this remains a topic of vigorous debate. In this talk, I will report on my recent work, relying on a new point source catalog (obtained by the Fermi-LAT collaboration), that sheds light on this controversial topic. After giving some background on the excess, I will discuss various metrics that have been used to try to understand its true nature. I will show that the large majority of bright sources that were previously suggested to be members of the excess are indeed contained in the new Fermi-LAT point source catalog -- and yet, despite masking out these sources (so that they cannot contribute to the excess), the excess remains just as bright in our new fit to the data. I will go on to discuss the implications of our findings for the two most popular interpretations of the excess.

Date: 
Thursday, December 19, 2019 - 4:00pm to 5:00pm
Location: 
BL 339
Type of Event (for grouping events):

Confronting Anomalies at Reactor Antineutrino Experiments

Date: 
Thursday, September 12, 2019 - 2:00pm to 3:00pm
Location: 
CP 179
Type of Event (for grouping events):

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